Hi people I need some help I have a my95
Sti fitting with a few mods fmic, gt3076 turbo , Simtek
Ect , anyway all was fine but changed the clutch around 2 weeks
Ago and wrapped my headers and changed plugs and oil.
But since doing the work when I drive the car all is fine however
When I got full boost 1.6bar the car splitters and coughts and holds back
I have checked the coil packs for cracks, and checked pipes ect but still
No change any idea what could cause this 1st and second seem ok but it's more
When I get into 3rd and above it just splutters and holds back. Any idea as to what it could be or what could be causeing the issue as it's annoying me now
I have stopped driving the car until I can figure out the issue, any advise would be great 👍

 

May be worth whipping the plugs out and checking the gaps in case you've accidentally closed/opened one up fitting them.

What plugs did you fit? Same ones that were in it before?

 

NHL iridium spark plugs heat grade 8 plugs I got them of eBay
As the shop had sold out but the issue has been there since I changed the plugs
Maybe it's worth me sticking the old ones back in as they was only a few thousand miles old

 

Ngk sorry NHL and I think last plugs were heat grade 7

 

Do that and see if the problem goes away.

 

I'll give it a try and see how it gets on

 

What should they be gapped at again

 

0.6 to 0.8

 

6 is standard, 7 is cooler, not sure about 8s

 

These are the plugs I fitted are they correct plugs or do I need to go back to 7s

Look at this on eBay:

http://pages.ebay.com/link/?nav=item...d=110826643030

SUBARU IMPREZA STI WRX NGK IRIDIUM SPARK PLUGS HEAT #8

 

What plugs are they? What code? e.g. PFR7B

To be honest I wouldn't buy anything from an advert as vague as that.

 

Heat grade 8 plugs are recommended above 500bhp, heat grade 7 gapped at .65mm are also acceptable at that level, the spluttering feeling is the high airflow at high boost blowing the spark out, ive had the same problem on my last mapping session so ive replaced all the coilpacks and will be upgrading my plugs to bkr8eix.

Good luck

 

The plugs I fitted in the car are bkr8eix
They are only few days old and I have checked all the coil
Packs and they all look fine and 2 are new aswell

 

They may be too much plug for the state of tune of your car as they are recommended for highly tuned/racing engines.

I use the uprated NGK PFR7B in my V3 STi which is mildly tuned and they seem to work well.

 

Given he has a 3076 turbo i would think they are the right plugs for his state of tune.

I would suggest data logging if possible.

Does the sputtering happen at a particular rpm

 

I'll have a look if the issue happens at a certain rpm
But seemed in 3,4,5 gear on full boost at higher rpm after 5k
But the car was perfect I just fitted a new clutch a new set of plugs and
Did a oil change, out of Curiosity would a little blow as think maybe I have a little blow
Between my up pipe and headers but not to sure bu would that cause these issues if
It did

 

I tend to think the same but as the only thing he's done is change the plugs they must be the prime suspects.

Does the CEL come on when it "splutters"?

 

Well the car has Simtek ecu but when it splutters
The cel light does go crazy at times but I'm putting that down to the splutter
the only thing I could imagine it being is the plugs as apart from changing them and
Wrapping headers and down pipe and changing clutch that was all that was done

 

If the car had a blow between the uppipe and headers
Would that cause the issues that I have, or does it sound more like a plug issue

 

I'd go with a newage coilpack conversion as it could be you coils or ignighter, at them levels of power I doubt the gc8 coils are doable

And yes get that blow sorted too

 

But the car has been running spot on with the cool packs for last year then changed clutch, plugs and oil and now have boost issue I'll start with changing plugs and go from there

 

Hi there

As above I would go with new age coilpack conversion,they should be improvement over older coilpacks

Those spark plugs we are run on our wagon without the issue,what spark plugs are you run previously,did you run same or different ?


Thanks,Jura

 

Ok people so a update I have changed the plugs checked all the cool packs sorted
Exhaust blow and now it is still holding back on boost but has also dropped from 1.6 bar to 1 bar of boost any ideas of what it could be I'm
Loosing patient with the car now

 

Take it to a specialist. You will waste time and money trying to diagnose it and they will find it in no time.

 

When you say "dropped to 1bar of boost" do you mean the car wont boost past 1 bar or its now spluttering at 1bar when it didnt before?

Do you have avcs by any chance?

I think your best getting it booked in with your mapper and get some data logging done, that will rule out a lot of possible issues

 

It boosts slightly over 1 bar but seems to splutter it is fitted with Simtek ecu so can read the codes if it's throwing any up but just weird how all was fine I change the clutch now all these issues

 

Reading codes only helps if there are codes to be read and even then they are quite vague, data logging by an experienced mapper is what you need as they can view all the engine parameters and they know what should be doing what, if there are any unusual values to any parameter they will know where, what and have rough ideas why you are having issues

 

1 thing I have noticed is I have to boost gauges 1
In psi and one in bar and the psi one oftern reads 0 and flashs like there is no pressure what so ever were the bar one will sit at say 0.6 the psi on will drop to of the dial
And start flashing

 

Though I would post my reply up I have sorted the problem after checking plugs, coil packs, sensors , intercooler piping it turned out to be the dv that was to fault my hks bv wouldn't hold boost over 1 bar so fitted my friends valve and back to full boost again